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R. Cela - One of the best experts on this subject based on the ideXlab platform.
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The photochemical behaviour of five household pyrethroid insecticides and a synergist as studied by photo-solid-phase microextraction
Analytical and Bioanalytical Chemistry, 2007Co-Authors: M. Fernández-Álvarez, M. Lores, M. Llompart, C. García-jares, R. CelaAbstract:In the present study, solid-phase microextraction in photochemical studies was used to investigate UV light induced photodegradation of five pyrethroids (empenthrin, transfluthrin, allethrin, phenothrin and Cyphenothrin) and a synergist (piperonyl butoxide), which are common ingredients of household insecticides. Gas chromatography coupled with mass spectrometry was used to separate and tentatively identify the parent compounds and their corresponding photoproducts generated in the same polydimethylsiloxane fibre. Kinetics curves were obtained and apparent first-order rate constants and half-lives were estimated. Twenty-six photoproducts were tentatively identified and photodegradation pathways for the compounds investigated were proposed. It is a matter of some concern that three of the photoproducts identified [(3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid, 3-phenoxybenzaldehyde and (3-phenoxyphenyl)methanol] have been reported to be endocrine disruptors. There is no record of previous studies of Cyphenothrin and empenthrin photodegradation, and therefore the present study represents the first attempt to elucidate the photochemical behaviour of these compounds. Figure Photo-SPME for Pyrethroids
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The photochemical behaviour of five household pyrethroid insecticides and a synergist as studied by photo-solid-phase microextraction.
Analytical and Bioanalytical Chemistry, 2007Co-Authors: M. Fernández-Álvarez, M. Lores, M. Llompart, C. García-jares, R. CelaAbstract:In the present study, solid-phase microextraction in photochemical studies was used to investigate UV light induced photodegradation of five pyrethroids (empenthrin, transfluthrin, allethrin, phenothrin and Cyphenothrin) and a synergist (piperonyl butoxide), which are common ingredients of household insecticides. Gas chromatography coupled with mass spectrometry was used to separate and tentatively identify the parent compounds and their corresponding photoproducts generated in the same polydimethylsiloxane fibre. Kinetics curves were obtained and apparent first-order rate constants and half-lives were estimated. Twenty-six photoproducts were tentatively identified and photodegrada- tion pathways for the compounds investigated were proposed. It is a matter of some concern that three of the photoproducts identified ((3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane- carboxylic acid, 3-phenoxybenzaldehyde and (3-phenoxy- phenyl)methanol) have been reported to be endocrine disruptors. There is no record of previous studies of Cyphenothrin and empenthrin photodegradation, and therefore the present study represents the first attempt to elucidate the photochemical behaviour of these compounds.
Ligang Chen - One of the best experts on this subject based on the ideXlab platform.
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Simple one-step preconcentration and cleanup with a micellar system for high performance liquid chromatography determination of pyrethroids in traditional Chinese medicine
Analytical Methods, 2020Co-Authors: Ligang Chen, Wenjuan XingAbstract:A novel but simple one-step preconcentration and cleanup using a micellar system was developed to extract and preconcentrate four pyrethroids including beta-cyfluthrin, cyhalothrin, Cyphenothrin and permethrin in traditional Chinese medicine with the use of the non-ionic surfactant Triton™ X-114. Before the high performance liquid chromatography analysis, a cleanup stage by adding an appropriate sorbent to remove the interfering components from the extracts was optimized. Based on results from the analysis, the best recoveries (86.8% to 94.3%) were obtained by preconcentration with 15% (m/v) sodium chloride, 2 : 1 (g g−1) of activated carbon/sample, and equilibration at 60 °C for 40 min, which was after a micellar extraction with 7.0% (v/v) Triton™ X-114, liquid : solid ratio of 20 : 1 (mL g−1), and an ultrasonic extraction time of 20 min at pH 7.0. The results of the four pyrethroids were linear within the range of 0.06–6.00 μg g−1. The limits of detection of beta-cyfluthrin, cyhalothrin, Cyphenothrin and permethrin were 0.0108, 0.0086, 0.0083 and 0.0092 μg g−1, respectively. Consequentially the method was applied for the extraction and determination of the four pyrethroids in different traditional Chinese medicines (Rhubarb, Herba lysimachiae, Ardisia japonica and the fruit of Camptotheca acuminata). Based on these results, the proposed method was a simple, effective and environmental friendly technique for the analysis of pyrethroid residues.
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quantum dots coated with molecularly imprinted polymer as fluorescence probe for detection of Cyphenothrin
Biosensors and Bioelectronics, 2015Co-Authors: Ligang ChenAbstract:Abstract A newly designed molecularly imprinted polymer (MIP) material was fabricated and successfully utilized as recognition element to develop a quantum dots (QDs) based MIP-coated composite for selective recognition of the template Cyphenothrin. The MIP-coated QDs were characterized by fluorescence spectrophotometer, Fourier transform infrared spectroscopy, transmission electron microscope, dynamic light scattering and X-ray powder diffraction. The fluorescence of the coated QDs is quenched on loading the MIP with Cyphenothrin, and the effect is much stronger for the MIP than for the non-imprinted polymer, which indicates the MIP could as a recognition template composite. This method can detect down to 9.0 nmol L −1 of Cyphenothrin in water, and a linear relationship has been obtained covering the concentration range of 0.1–80.0 μmol L −1 . The method has been used in the determination of Cyphenothrin in water samples and gave recoveries in the range from 88.5% to 97.1% with relative standard deviations in the range of 3.1–6.2%. The present study provides a new and general strategy to fabricate inorganic–organic MIP-coated QDs with highly selective recognition ability in aqueous media and is desirable for chemical probe application.
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Development of magnetic molecularly imprinted polymers based on carbon nanotubes – Application for trace analysis of pyrethroids in fruit matrices
Journal of Chromatography A, 2014Co-Authors: Guifu Ma, Ligang ChenAbstract:Abstract The sensitive and efficient magnetic molecularly imprinted polymers (MMIPs) were successfully synthesized using carbon nanotubes as matrix and Fe3O4 particles as magnetic ingredient. Tetraethyl orthosilicate was used as modification material of the carbon nanotubes. Cyhalothrin, methacrylic acid and ethylene glycol dimethacrylate were used as template molecule, functional monomer and cross-linker, respectively. Azo-isobutyronitrile and polyvinylpyrrolidone were used as initiator and dispersant, respectively. The MMIPs were used for the separation of pyrethroids including beta-cyfluthrin, cyhalothrin, Cyphenothrin and permethrin in fruit samples followed by high performance liquid chromatography analysis. The polymers were characterized with Fourier transform infrared spectrometry, Brunauer–Emmett–Teller method, transmission electron microscopy and a physical property measurement system. The isothermal absorption experiment, kinetics absorption experiment and selectivity of MMIPs were studied in detail. Scatchard analysis revealed that two kinds of different binding sites existed in MMIPs. The maximum adsorption capacities of two binding sites were 65.21 and 189.83 mg g−1, and dissociation constants were 7.11 and 30.40 μg mL−1, respectively. The kinetic property of MMIPs was well fitted to the second-order equation. The selectivity experiment indicated that MMIPs had higher selectivity toward cyhalothrin and its structural analogs than reference compound. The feasibility of detecting pyrethroids from real samples was testified in spiked fruit samples with different concentrations (0.025, 0.25 and 2.5 mg kg−1). The LODs of beta-cyfluthrin, cyhalothrin, Cyphenothrin and permethrin were 0.0072, 0.0035, 0.0062 and 0.0068 mg kg−1, respectively. Precisions of intra-day and inter-day ranging from 2.6% to 4.3% and 4.2% to 5.6% were obtained, respectively. This method was applied to determine pyrethroids in different fruit samples including apple, pear, orange, grape and peach, and satisfied recoveries (82.4–101.7%) were obtained.
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Determination of Pyrethroids in Environmental Waters Using Magnetic Chitosan Extraction Coupled with High Performance Liquid Chromatography Detection
Analytical Letters, 2013Co-Authors: Jia Tong, Ligang ChenAbstract:The magnetic chitosan was prepared by adding chitosan, Fe2+ and Fe3+ into a basic precipitant of NaOH solution. The synthetic magnetic chitosan was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and physical properties. The adsorption characteristics of magnetic chitosan for extracting pyrethroids from water samples were investigated. The analytes were separated by magnetic solid phase extraction and determined by high performance liquid chromatography. The optimum conditions of adsorption experiments were obtained: the amount of sorbent was 80 mg, the extraction time was 20 min, the washing solvent was 50% aqueous methanol, and the eluent was acetonitrile-acetic acid (99: 1, v/v). The obtained linearity of three pyrethroids was in the range of 30–3000 ng L−1. The detection limits of beta-cyfluthrin, cyhalothrin, and Cyphenothrin were 7.5, 5.6, and 6.1 ng L−1, respectively. The intra-day and inter-day precisions of three pyrethroids were...
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Preparation of magnetic carbon nanotubes for separation of pyrethroids from tea samples
Mikrochimica Acta, 2013Co-Authors: Ligang ChenAbstract:Magnetic carbon nanotubes (MCNTs) have been synthesized by chemical deposition of Fe3O4 nanoparticles onto carbon nanotubes. They were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction and physical property measurement system. The MCNTs were used as the sorbents for the extraction of pyrethroids including beta-cyfluthrin, cyhalothrin and Cyphenothrin from tea samples. The extraction conditions, such as the amount of magnetic sorbent, shaking time and rate, washing and eluting solution have been fully investigated. The analytes desorbed from MCNTs were determined by HPLC with UV detection. Under the optimal conditions, the linearity of the method is in the range of 0.05–25 μg g−1. The limits of detection of the three pyrethroids are 0.017, 0.010 and 0.018 μg g−1, respectively. The relative standard deviations of within- and between-day range from 3.5 % to 6.4 %, and from 4.5 % to 29 7.3 %, respectively. In all three spiked levels (0.05, 0.5 and 5 μg g-1), the recoveries of pyrethroids are in the range of 82.2 %–94.4 %. This method is much faster and more effective than traditional methods, and it is promising for the analysis of pesticides residues.
Shaohua Chen - One of the best experts on this subject based on the ideXlab platform.
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mechanism of allethrin biodegradation by a newly isolated sphingomonas trueperi strain cw3 from wastewater sludge
Bioresource Technology, 2020Co-Authors: Pankaj Bhatt, Yaohua Huang, Alagarasan Jagadeesh Kumar, Eldon R. Rene, Shaohua ChenAbstract:Abstract The main aim of this study was to investigate and characterize the bacterial strain that has the potential to degrade allethrin. The isolated strain, Sphingomonas trueperi CW3, degraded allethrin (50 mg L−1) in batch experiments within seven days. The Box-Behnken design optimized allethrin degradation and had a confirmation of 93% degradation at pH 7.0, at a temperature of 30 °C and an inocula concentration of 100 mg L−1. The results from gas chromatography and mass spectrometry analysis confirmed the existence of nine metabolites from the degradation of allethrin with strain CW3. The cleavage of the ester bond, followed by the degradation of the five-carbon rings, was allethrin’s primary degradation pathway. The strain CW3 also degraded other widely applied synthetic pyrethroids such as Cyphenothrin, bifenthrin, permethrin, tetramethrin, β-cypermethrin and chlorempenthrin. Furthermore, in experiments performed with sterilized soil, strain CW3 based bioaugmentation effectively removed allethrin at a significantly reduced half-life.
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new insights into the microbial degradation of d Cyphenothrin in contaminated water soil environments
Microorganisms, 2020Co-Authors: Yaohua Huang, Pankaj Bhatt, Alagarasan Jagadeesh Kumar, Eldon R. Rene, Wenping Zhang, Shimei Pang, Shaohua ChenAbstract:Persistent use of the insecticide D-Cyphenothrin has resulted in heavy environmental contamination and public concern. However, microbial degradation of D-Cyphenothrin has never been investigated and the mechanism remains unknown. During this study, for the first time, an efficient D-Cyphenothrin-degrading bacterial strain Staphylococcus succinus HLJ-10 was identified. Response surface methodology was successfully employed by using Box-Behnken design to optimize the culture conditions. At optimized conditions, over 90% degradation of D-Cyphenothrin (50 mg·L−1) was achieved in a mineral salt medium within 7 d. Kinetics analysis revealed that its half-life was reduced by 61.2 d, in comparison with the uninoculated control. Eight intermediate metabolites were detected in the biodegradation pathway of D-Cyphenothrin including cis-D-Cyphenothrin, trans-D-Cyphenothrin, 3-phenoxybenzaldehyde, α-hydroxy-3-phenoxy-benzeneacetonitrile, trans-2,2-dimethyl-3-propenyl-cyclopropanol, 2,2-dimethyl-3-propenyl-cyclopropionic acid, trans-2,2-dimethyl-3-propenyl-cyclopropionaldehyde, and 1,2-benzenedicarboxylic acid, dipropyl ester. This is the first report about the degradation of D-Cyphenothrin through cleavage of carboxylester linkage and diaryl bond. In addition to degradation of D-Cyphenothrin, strain HLJ-10 effectively degraded a wide range of synthetic pyrethroids including permethrin, tetramethrin, bifenthrin, allethrin, and chlorempenthrin, which are also widely used insecticides with environmental contamination problems. Bioaugmentation of D-Cyphenothrin-contaminated soils with strain HLJ-10 substantially enhanced its degradation and over 72% of D-Cyphenothrin was removed from soils within 40 d. These findings unveil the biochemical basis of a highly efficient D-Cyphenothrin-degrading bacterial isolate and provide potent agents for eliminating environmental residues of pyrethroids.
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New Insights into the Microbial Degradation of D-Cyphenothrin in Contaminated Water/Soil Environments.
Microorganisms, 2020Co-Authors: Yaohua Huang, Pankaj Bhatt, Alagarasan Jagadeesh Kumar, Eldon R. Rene, Wenping Zhang, Shimei Pang, Shaohua ChenAbstract:Persistent use of the insecticide D-Cyphenothrin has resulted in heavy environmental contamination and public concern. However, microbial degradation of D-Cyphenothrin has never been investigated and the mechanism remains unknown. During this study, for the first time, an efficient D-Cyphenothrin-degrading bacterial strain Staphylococcus succinus HLJ-10 was identified. Response surface methodology was successfully employed by using Box-Behnken design to optimize the culture conditions. At optimized conditions, over 90% degradation of D-Cyphenothrin (50 mg·L−1) was achieved in a mineral salt medium within 7 d. Kinetics analysis revealed that its half-life was reduced by 61.2 d, in comparison with the uninoculated control. Eight intermediate metabolites were detected in the biodegradation pathway of D-Cyphenothrin including cis-D-Cyphenothrin, trans-D-Cyphenothrin, 3-phenoxybenzaldehyde, α-hydroxy-3-phenoxy-benzeneacetonitrile, trans-2,2-dimethyl-3-propenyl-cyclopropanol, 2,2-dimethyl-3-propenyl-cyclopropionic acid, trans-2,2-dimethyl-3-propenyl-cyclopropionaldehyde, and 1,2-benzenedicarboxylic acid, dipropyl ester. This is the first report about the degradation of D-Cyphenothrin through cleavage of carboxylester linkage and diaryl bond. In addition to degradation of D-Cyphenothrin, strain HLJ-10 effectively degraded a wide range of synthetic pyrethroids including permethrin, tetramethrin, bifenthrin, allethrin, and chlorempenthrin, which are also widely used insecticides with environmental contamination problems. Bioaugmentation of D-Cyphenothrin-contaminated soils with strain HLJ-10 substantially enhanced its degradation and over 72% of D-Cyphenothrin was removed from soils within 40 d. These findings unveil the biochemical basis of a highly efficient D-Cyphenothrin-degrading bacterial isolate and provide potent agents for eliminating environmental residues of pyrethroids.
M. Fernández-Álvarez - One of the best experts on this subject based on the ideXlab platform.
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The photochemical behaviour of five household pyrethroid insecticides and a synergist as studied by photo-solid-phase microextraction
Analytical and Bioanalytical Chemistry, 2007Co-Authors: M. Fernández-Álvarez, M. Lores, M. Llompart, C. García-jares, R. CelaAbstract:In the present study, solid-phase microextraction in photochemical studies was used to investigate UV light induced photodegradation of five pyrethroids (empenthrin, transfluthrin, allethrin, phenothrin and Cyphenothrin) and a synergist (piperonyl butoxide), which are common ingredients of household insecticides. Gas chromatography coupled with mass spectrometry was used to separate and tentatively identify the parent compounds and their corresponding photoproducts generated in the same polydimethylsiloxane fibre. Kinetics curves were obtained and apparent first-order rate constants and half-lives were estimated. Twenty-six photoproducts were tentatively identified and photodegradation pathways for the compounds investigated were proposed. It is a matter of some concern that three of the photoproducts identified [(3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid, 3-phenoxybenzaldehyde and (3-phenoxyphenyl)methanol] have been reported to be endocrine disruptors. There is no record of previous studies of Cyphenothrin and empenthrin photodegradation, and therefore the present study represents the first attempt to elucidate the photochemical behaviour of these compounds. Figure Photo-SPME for Pyrethroids
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The photochemical behaviour of five household pyrethroid insecticides and a synergist as studied by photo-solid-phase microextraction.
Analytical and Bioanalytical Chemistry, 2007Co-Authors: M. Fernández-Álvarez, M. Lores, M. Llompart, C. García-jares, R. CelaAbstract:In the present study, solid-phase microextraction in photochemical studies was used to investigate UV light induced photodegradation of five pyrethroids (empenthrin, transfluthrin, allethrin, phenothrin and Cyphenothrin) and a synergist (piperonyl butoxide), which are common ingredients of household insecticides. Gas chromatography coupled with mass spectrometry was used to separate and tentatively identify the parent compounds and their corresponding photoproducts generated in the same polydimethylsiloxane fibre. Kinetics curves were obtained and apparent first-order rate constants and half-lives were estimated. Twenty-six photoproducts were tentatively identified and photodegrada- tion pathways for the compounds investigated were proposed. It is a matter of some concern that three of the photoproducts identified ((3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane- carboxylic acid, 3-phenoxybenzaldehyde and (3-phenoxy- phenyl)methanol) have been reported to be endocrine disruptors. There is no record of previous studies of Cyphenothrin and empenthrin photodegradation, and therefore the present study represents the first attempt to elucidate the photochemical behaviour of these compounds.
Ruchika Solanki - One of the best experts on this subject based on the ideXlab platform.
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efficacy of a proprietary formulation of fipronil s methoprene Cyphenothrin against ixodes scapularis tick infestations on dogs
Parasites & Vectors, 2015Co-Authors: Doug Carithers, William R Everett, Sheila J Gross, Ruchika SolankiAbstract:Background Efficacy of FRONTLINE® TRITAK® For Dogs (fipronil/(S)-methoprene/Cyphenothrin, Merial, Inc., Duluth, GA) against Ixodes scapularis was evaluated in two separate, but concurrent laboratory studies.
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Efficacy of a proprietary formulation of fipronil/(S)-methoprene/Cyphenothrin against Ixodes scapularis tick infestations on dogs
Parasites & Vectors, 2015Co-Authors: Doug Carithers, William R Everett, Sheila J Gross, Ruchika SolankiAbstract:Background Efficacy of FRONTLINE® TRITAK® For Dogs (fipronil/(S)-methoprene/Cyphenothrin, Merial, Inc., Duluth, GA) against Ixodes scapularis was evaluated in two separate, but concurrent laboratory studies.
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Efficacy of a proprietary formulation of fipronil/(S)-methoprene/Cyphenothrin against Ixodes scapularis tick infestations on dogs
Parasites & Vectors, 2015Co-Authors: Doug Carithers, William R Everett, Sheila J Gross, Ruchika SolankiAbstract:Background Efficacy of FRONTLINE® TRITAK® For Dogs (fipronil/(S)-methoprene/Cyphenothrin, Merial, Inc., Duluth, GA) against Ixodes scapularis was evaluated in two separate, but concurrent laboratory studies. Methods One day after topical treatment with placebo or active, dogs (n = 24) were infested with 50 unfed adult Ixodes scapularis ticks, with repeat infestations on Days 7, 14, 21 and 28. The number of live ticks was counted at 6 hours post-infestation in the first study (n = 12) and at 24 hours post-infestation in the second study (n = 12). Results Observed efficacies in study 1 were 93-99 % at 6 hour assessments on Day 1 through Day 28 and in the second study, 98-100 % at 24 hour assessments, occurring on Day 2 through Day 29. Conclusions A single dose of FRONTLINE® TRITAK® For Dogs (fipronil/(S)-methoprene/Cyphenothrin) (0.67 ml or 1.34 ml) prevented the establishment of a new infestation following treatment, as well as the repeated weekly re-infestations with Ixodes scapularis ticks, for 4 weeks.
